I know the feeling of "Making things work" but to be honest I think you might be better off with getting a 3D machine designed for that from the ground up.

If you want to try to make it work them go with less pitch and more diameter. Like a 12-4 or the APC 12.25-3.75. Move the CG back farther, by all means enlarge the elevator and rudder, Ailerons if possible.